IceWM is very configurable. Have you checked out their documentation? http://www.icewm.org/manual/icewm.html#toc10
Have you copied the /usr/share/icewm config files over to your ~/.icewm directory? This way you can tweak to your heart's content. Not 100% sure of the config file source path, but look at their web site to be sure. As for fonts, I believe that is theme specific, so you may have to play around with that.